Electrical Resistivity Tomography (ERT) method was applied to study a fragment of the Pieniny Klippen Belt (PKB), which has been investigated for more than 100 years. The study area is located in the Spisz Pieniny Mountains of southern Poland. The PKB in this region includes a characteristic belt of limestone outcrops. ERT turned out to be an effective method to determine the structure of this part of the PKB, revealing its zonal nature and documenting the presence of limestone olistoliths and allowing estimates of their sizes. Moreover, we show that proper planning and conducting of ERT measurements in the field is critical to the effective use of resistivity data for geological inference and interpretation. This has been demonstrated by performing appropriate numerical and analogue ERT modeling that shows possible ambiguous results arising from the field ERT survey. Awareness of this issue can help researchers avoid and minimize false interpretation of ERT data.